When a cylindrical electrophotographic photoreceptor (hereinafter occasionally referred to as a photoreceptor drum) is produced, a coating layer is generally formed by immersing a conductive cylindrical substrate into a photosensitive layer composition or coating compositions for an interlayer and a surface protective layer.
In such a case, since the conductive cylindrical substrate is immersed into a coating composition, a coating layer is formed on the entire surface of the conductive cylindrical body. When a photoreceptor drum, which is subjected to formation of the coating layer on the entire surface, is mounted on an electrophotographic image forming apparatus, occasionally, it becomes impossible to accurately carry out hitting due to peeling of the coating layer through contact with rollers which hits development units. Further, occasionally, it becomes impossible to use the photoreceptor drum as a contact point for grounding. As a result, it is preferable to remove the coating layer adhered on both edges of the photoreceptor drum.
Methods for removing such a coating layer include a method in which edges of a photoreceptor drum are immersed in a solvent and is subjected to vibration employing ultrasonic waves (Japanese Patent Application Open to Public Inspection No. 63-311357), a rubbing method employing a brush (Japanese Patent Application Open to Public Inspection Nos. 3-60782, 4-141663, 5-142789, 10-207084, 11-184100, and 11-194509), and in addition, a removing method employing tape.
For example, a method (Japanese Patent Application Open to Public Inspection No. 6-138670) is known in which tape which is comprised of thermally fusible type non-woven fabric is successively unwound, and the resulting tape is impregnated with solvent and thereafter, the impregnated tape comes into contact with a photoreceptor drum, thereby the removal is carried out. A method (Japanese Patent Application Open to Public Inspection No. 9-281725) is also known in which tape comprised of non-woven fabric, having an uneven structure on one surface, is employed.
Based on the investigations performed by the inventors of the present invention, however, in any methods, the following problems were found. Edges of the coating layer of a photoreceptor drum, in which the coating layer had been removed, tended to peel off. Insufficient cleaning occurred due to accumulation of toner at the edges in which the coating layer had been removed and toner scattering occurred, resulting in staining of the interior of the apparatus. Due to those, durability of the photoreceptor drum as well as cleaning member (such as cleaning means) degrades. As a result, it has been demanded that edges of the coating layer are shaped so that such problems do not occur.
Particularly, during the repeated use at high temperature and high humidity, toner is adhere-accumulated at the edges of the photoreceptor, whereby the torque between the cleaning blade and the photoreceptor varies, resulting in peeling of the coating layer at edges. Particularly, when peeling occurs, or coagulated toner which adheres to the aforesaid portion is mixed with developer as foreign matter, insufficient charging as well as insufficient cleaning results in black spots, whereby image quality is occasionally degraded.
Particularly, in recent years, in order to utilize excellent image quality which is an advantage of the electrophotographic image forming method, and to further improve the image quality, development toner, comprised of smaller size particles with uniform shape, has been commonly employed. In such cases, the aforesaid problems are more pronounced.
When a toner having smaller particle size are employed in combination with a photoreceptor, photosensitive coating at the end portion of which has been removed by wiping, wave-like cleaning defect is found at center of image forming area. The defect is supposed to be caused by shape of end portion of the photoreceptor. However it appears at the center portion of image forming area as fog of fine mottle, and step uneven image may appear even after the final image.